Delta printing strange shapes

  • I've run into a rather strange issue while setting up my new build, I've been printing a simple bracket that's meant to be 32mm long by 24mm and 10mm thick, however the x and y axis are 2.5mm under and the z is 2mm under as well as its not square as it should be, any ideas?

  • Hi,

    Read about M579.

    It allows scaling each axis as needed to obtain correct sizes.

    Have you already verified that the steps-per-mm is correct (M92)?


  • post your config.g

  • ; Configuration file for Duet WiFi (firmware version 3)
    ; executed by the firmware on start-up
    ; generated by RepRapFirmware Configuration Tool v3.1.4 on Fri Nov 13 2020 09:47:15 GMT+0000 (Greenwich Mean Time)

    ; General preferences
    G90 ; send absolute coordinates...
    M83 ; ...but relative extruder moves
    M550 P"My Printer" ; set printer name
    M665 R168.619 L360 B125 H236 ; Set delta radius, diagonal rod length, printable radius and homed height
    M666 X0 Y0 Z0 ; put your endstop adjustments here, or let auto calibration find them

    ; Network
    M552 P0.0.0.0 S1 ; enable network and acquire dynamic address via DHCP
    M586 P0 S1 ; enable HTTP
    M586 P1 S1 ; enable FTP
    M586 P2 S1 ; enable Telnet

    ; Drives
    M569 P0 S1 ; physical drive 0 goes forwards
    M569 P1 S1 ; physical drive 1 goes forwards
    M569 P2 S1 ; physical drive 2 goes forwards
    M569 P3 S1 ; physical drive 3 goes forwards
    M584 X0 Y1 Z2 E3 ; set drive mapping
    M350 X16 Y16 Z16 E16 I0 ; configure microstepping without interpolation
    M92 X100 Y100 Z100.00 E663.00 ; set steps per mm
    M566 X1200.00 Y1200.00 Z1200.00 E1200.00 ; set maximum instantaneous speed changes (mm/min)
    M203 X18000.00 Y18000.00 Z18000.00 E1200.00 ; set maximum speeds (mm/min)
    M201 X1000.00 Y1000.00 Z1000.00 E1000.00 ; set accelerations (mm/s^2)
    M906 X1000 Y1000 Z1000 E800 I30 ; set motor currents (mA) and motor idle factor in per cent
    M84 S30 ; Set idle timeout

    ; Axis Limits
    M208 Z0 S1 ; set minimum Z

    ; Endstops
    M574 X2 S1 P"xstop" ; configure active-high endstop for high end on X via pin xstop
    M574 Y2 S1 P"ystop" ; configure active-high endstop for high end on Y via pin ystop
    M574 Z2 S1 P"zstop" ; configure active-high endstop for high end on Z via pin zstop

    ; Z-Probe
    M558 P5 R0.4 C"" H5 F1200 T6000 ; set Z probe type to effector and the dive height + speeds
    G31 P500 X0 Y0 Z-0.15 ; set Z probe trigger value, offset and trigger height
    M557 R85 S20 ; define mesh grid

    ; Heaters
    M308 S0 P"bedtemp" Y"thermistor" T100000 B3988 ; configure sensor 0 as thermistor on pin bedtemp
    M950 H0 C"bedheat" T0 ; create bed heater output on bedheat and map it to sensor 0
    M307 H0 A545.4 C739.1 D2.5 V24.3 B0 ; disable bang-bang mode for the bed heater and set PWM limit
    M140 H0 ; map heated bed to heater 0
    M143 H0 S120 ; set temperature limit for heater 0 to 120C
    M308 S1 P"e0temp" Y"thermistor" T100000 B3988 ; configure sensor 1 as thermistor on pin e0temp
    M950 H1 C"e0heat" T1 ; create nozzle heater output on e0heat and map it to sensor 1
    M307 H1 B0 S1.00 ; disable bang-bang mode for heater and set PWM limit

    ; Fans
    M950 F0 C"fan0" Q500 ; create fan 0 on pin fan0 and set its frequency
    M106 P0 S0 H1 T45 ; set fan 0 value. Thermostatic control is turned on

    ; Tools
    M563 P0 D0 H1 F0 ; define tool 0
    G10 P0 X0 Y0 Z0 ; set tool 0 axis offsets
    G10 P0 R0 S0 ; set initial tool 0 active and standby temperatures to 0C

    ; Custom settings are not defined

    ; Miscellaneous
    M575 P1 S1 B57600 ; enable support for PanelDue
    M911 S10 R11 P"M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000" ; set voltage thresholds and actions to run on power loss

  • I have managed to sort most of the issues out for some reason me e steps had reset to 80 when I updated my firmware instead of 100, however, I have now got the issue of the prints being out of scale. I printed a 100mm cube and my x axis came to 105mm and my y axis 95mm as well as my z axis being 105mm, however with a delta printer it isn't as simple as running a simple calculation and changing the e steps as it then throws the entire printer out of sync.

    Any ideas?

  • @Bewaren said in Delta printing strange shapes:

    M665 R168.619 L360 B125 H236 ; Set delta radius, diagonal rod length, printable radius and homed height
    M666 X0 Y0 Z0 ; put your endstop adjustments here, or let auto calibration find them

    this does not look like the result of the auto calibration.

    please read

  • I've now managed to solve this issue, one of my extrusions was very slightly bent, I am using exoslide brackets and hence it was throwing out the entire print. I've replaced this and now run into another issue.

    I am in the middle of making a floating / flying bracket for my titan extruder and when I print it my external dimensions are perfectly accurate, however any internal parts, such as the hole for the stepper motor and bolts are out by 0.8mm +/- 0.1mm. I believe the issue is that the slicer is printing one extra internal wall so to speak, with it being 0.4mm wide and running the full area it adds too 0.8mm. I am using the prusaslicer, any idea how to fix this?

  • @Bewaren That's typical for any printer, you calibrate based on straight lines, so when you start doing a tight curve the inside of the line is basically squished and the outside stretched, making excess material push toward the center reducing the hole.

    A common method and the easiest when you made the model yourself, is to address this in the model by adding some tolerance. Since the behavior should be consistent (it sounds like it is for you), at least for horizontal laying holes and vertical ones may be different from those but still the same to each other. For vertical printed holes there's also a technique to make them oval shaped in the model to get circular results in FDM prints. In openscad I leave a variable on hole diameter's (usually named fudge since it's my fudge factor), so I can just set that to add .2mm or whatever to give the clearance I want to all the holes for how the printer is presently behaving.

    Cura (and probably other slicers) has a setting to compensate the size for holes as well.

  • @lord-binky Adding a 0.8mm tolerance is ridiculous though, I can understand a 0.2mm tolerance and that's what I've been using for years, however in my new delta build it doesn't make any sense for it to be so far out.

  • Yeah... don't know squat about prusa slicer 😛 they do things a bit different. They got lots of modifiers and settings that can override perimeters on things like holes (local strengthening, volume modifier, and probably more). I tried looking at Prusa slicer's features and I had a flashback of the frustration I had with Cura in our definition of terms and how things should be related don't match up all that often when it comes to specifics.

  • @lord-binky What slicer do you use now?

  • @Bewaren Recently swapped to Cura, was using S3d before but I found that was one of the causes of my surface patterns.

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